1. Field of the Invention
The present invention relates to a plate-link chain and to a guide plate for a plate-link chain.
2. Description of the Related Art
Chains are known in many varieties from the existing art. Chains can be employed, for example, in the frictional transmission of torque in a chain-and-pulley transmission having an endless torque-transmitting means (CVT transmission), and in a positive-connection manner of torque transmission as pin chains, roller chains, or, for example, toothed chains. Such toothed chains can, in turn, have a hinged connection that includes two rocker pressure pieces that roll against each other for each hinged connection.
For example, different types of plates are used in toothed chains, since the chain must be guided transversely to its circulation direction. So-called guide plates are integrated into the chain specifically for those tasks, it being possible in principle to differentiate between internally guided and externally guided toothed chains. Hereby internally guided toothed chains are guided transversely to the circulation direction through special chain links in the region of the middle of their extension. A different possibility is realized in an externally guided chain, where the outermost link plates are of a special design that guides the chain; that is, the guide plates of the chain extend laterally beyond the gear with which they interact.
For those guide plates, in turn, a plurality of embodiments are known from the existing art, which result in part, among other things, from the load, which differs substantially from the load on the other chain links.
Fields of application for such toothed chains include, for example, timing chains, which connect the crankshaft of an internal combustion engine with the camshaft, at least indirectly, and thus control the valves that control the charge exchange process. The execution of such control chains or chain drives is known in the existing art and will not be discussed further here.
Another area of use for such toothed chains is represented, for example, by four-wheel drive concepts, where starting from a power divider transmission a portion of the driving power is conveyed to the rear wheels, for example through a cardan shaft, while the remaining part is conveyed through a chain drive of that sort that runs essentially parallel to the cardan shaft, which then conveys the power to the front wheels.
It is known from the existing art, such as U.S. Pat. No. 5,445,570, for example, to employ a press fit between the guide plate and the entire rocker pressure periphery, which fixes the two parts to each other. That press fit brings about very high stresses in the guide plate at the smallest radii. Furthermore, the reduced rigidity of the edge guide plate with respect to the tooth plate according to the existing art causes uniform elongation of the chain links, and thus a pitch that remains the same in the entire chain. That reduced rigidity is attained in various ways, for example through a deep notch on the axis of symmetry from the upper back of the guide plate, or through a lesser thickness of the guide plate. That notch, for its part, causes the edge plate or guide plate to bend open, because the neutral fiber is in the lower zone, as can also be seen in the drawing figures.
An object of the present invention is to provide a guide plate of a toothed chain having improved elastic properties of the entire plate and of the contact zone with the chain joint.